[PATCH 12/16] mm/ioremap: Add arch-specific callbacks on ioremap/iounmap calls

[Marc Zyngier]

Add a pair of hooks (ioremap_page_range_hook/iounmap_page_range_hook)
that can be implemented by an architecture.

Signed-off-by: Marc Zyngier <maz at kernel.org>
---
 include/linux/io.h |  3 +++
 mm/ioremap.c       | 13 ++++++++++++-
 mm/vmalloc.c       |  8 ++++++++
 3 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/include/linux/io.h b/include/linux/io.h
index 9595151d800d..0ffc265f114c 100644
--- a/include/linux/io.h
+++ b/include/linux/io.h
@@ -21,6 +21,9 @@ void __ioread32_copy(void *to, const void __iomem *from, size_t count);
 void __iowrite64_copy(void __iomem *to, const void *from, size_t count);
 
 #ifdef CONFIG_MMU
+void ioremap_page_range_hook(unsigned long addr, unsigned long end,
+			     phys_addr_t phys_addr, pgprot_t prot);
+void iounmap_page_range_hook(phys_addr_t phys_addr, size_t size);
 int ioremap_page_range(unsigned long addr, unsigned long end,
 		       phys_addr_t phys_addr, pgprot_t prot);
 #else
diff --git a/mm/ioremap.c b/mm/ioremap.c
index 8ee0136f8cb0..bd77a86088f2 100644
--- a/mm/ioremap.c
+++ b/mm/ioremap.c
@@ -28,10 +28,21 @@ early_param("nohugeiomap", set_nohugeiomap);
 static const unsigned int iomap_max_page_shift = PAGE_SHIFT;
 #endif	/* CONFIG_HAVE_ARCH_HUGE_VMAP */
 
+void __weak ioremap_page_range_hook(unsigned long addr, unsigned long end,
+				    phys_addr_t phys_addr, pgprot_t prot)
+{
+}
+
 int ioremap_page_range(unsigned long addr,
 		       unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
 {
-	return vmap_range(addr, end, phys_addr, prot, iomap_max_page_shift);
+	int ret;
+
+	ret = vmap_range(addr, end, phys_addr, prot, iomap_max_page_shift);
+	if (!ret)
+		ioremap_page_range_hook(addr, end, phys_addr, prot);
+
+	return ret;
 }
 
 #ifdef CONFIG_GENERIC_IOREMAP
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index d5cd52805149..af18a6141093 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -38,6 +38,7 @@
 #include <linux/pgtable.h>
 #include <linux/uaccess.h>
 #include <linux/hugetlb.h>
+#include <linux/io.h>
 #include <asm/tlbflush.h>
 #include <asm/shmparam.h>
 
@@ -2551,6 +2552,10 @@ static void vm_remove_mappings(struct vm_struct *area, int deallocate_pages)
 	set_area_direct_map(area, set_direct_map_default_noflush);
 }
 
+void __weak iounmap_page_range_hook(phys_addr_t phys_addr, size_t size)
+{
+}
+
 static void __vunmap(const void *addr, int deallocate_pages)
 {
 	struct vm_struct *area;
@@ -2574,6 +2579,9 @@ static void __vunmap(const void *addr, int deallocate_pages)
 
 	kasan_poison_vmalloc(area->addr, get_vm_area_size(area));
 
+	if (area->flags & VM_IOREMAP)
+		iounmap_page_range_hook(area->phys_addr, get_vm_area_size(area));
+
 	vm_remove_mappings(area, deallocate_pages);
 
 	if (deallocate_pages) {
-- 
2.30.2